Fluid pump



March 19, W58 E. F. KLESSIG ET AL ,7 3,373,692

FLUID PUMP Filed Dec. 9, 1965 g Z. 4 b\ 40 7 19 17 rates 3,373,692 FLUID PUMP Ernst F. Klessig and Lazarus H. Dadian, Racine, Wis., assignors to Racine Hydraulics & Machinery, Inc., a corporation of Wisconsin Filed Dec. 9, 1965, Ser. No. 512,625 4 Claims. (Cl. 103-420) ABSTRACT OF THE DISCLOSURE A variable volume hydraulic vane-type pump having a passage with an inlet connected to the space between adjacent pump vanes at a location blocked from the pressure zone of the pump and in advance of the suction port to release decompressed fluid from the space in advance of the suction port and avoid aeration of fluid in the inlet zone of the pump.

This invention relates to fluid pumps and more particularly to a variable volume pump having improved governor control and other advantages resulting from removal of pressure fluid and decompressed fluid from the pump.

An object of this invention is to provide a new and improved pump.

Another object of this invention is to provide a variable volume pump having a rotor and rotor ring with a governor for controlling the positioning of the rotor ring and with a suction port for supplying fluid to the pump and a pressure port for removal of fluid and with means in advance of the suction port for removing oil from the pump in advance of the suction port to release pressure acting on the rotor ring and avoid emulsifying of the oil.

Still another object of the invention is to provide a variable volume vane type pump having a casing rotatably mounting a rotor and with a rotor ring surrounding the rotor and positionable by a yieldable governor with the rotor ring movable between a position concentric with the rotor and various positions non-concentric therewith, there being a port plate at one side of the rotor and rotor ring, provided with pressure and suction ports and the port plate having a passage with an inlet connecting with the space between the rotor and rotor ring immediately in advance of the suction port and an outlet communicating with a drain area of the pump whereby decompressed oil and emulsion can be removed from the.

pump in advance of the pump receiving oil from the suction port whereby a full charge of oil is received and handled by the pump.

Further objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a vertical section taken generally along the line 1-1 in FIG. 2 and showing one embodiment of our invention;

FIG. 2 is a vertical section taken generally along the line 22 in FIG. 1;

FIG. 3 is a fragmentary section taken along the line 3-3 in FIG. 1; and

FIG. 4 is a view similar to FIG. 3 ring in a deadhead position.

While this invention is susceptible of embodiment in many different forms, there is shOWn in the drawings and will herein be described in detail an embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Variable volume vane type pumps are in common use showing the rotor Patented Mar. 19, 1968 and embody a rotor and surrounding rotor ring with the rotor ring being positionable in different positions relative to the rotor under the control of a governor and system pressure. As the vanes move past crossover toward the suction port, oil in the chamber between adjacent vanes is decompressed when the rotor is in any position non-concentric with the rotor. Aeration occurs when a chamber opens to the suction port and exhausts a jet stream of oil into the port. This has the detrimental effect of carrying around to the pressure side of the pump a partial charge of oil delivered by the suction port and also some emulsion so that a full charge of oil is not delivered. This results in pressure oil back-flowing from the pressure port into the chambers between vanes with a resulting adverse effect on governor control. Even in deadhead operation with the rotor ring nearly concentric with the rotor, there are improved results from the means provided by this invention in that there is increased external drain flow which keeps the pump cooler and results in removal of any emulsion in the pump chambers. Also, in deadhead operation, removal of pressure from the chamber results in avoiding the carry-over of pressure acting against the rotor ring and the governor. This makes the governor control more accurate and substantially reduces the required spring rate of the governor spring. The passage means of this invention has resulted in making the pump quieter in deadhead operation and it is believed probable that less horsepower is required to operate the pump when in deadhead operation.

Referring to the drawings, a variable volume pump is shown in FIGS. 1 and 2 having a casing formed of parts 10 and 11 connected together by bolts, one of which is indicated at 12, and received in threaded openings 13 in the casing part 10. The pump has a drive shaft 14 mounted by suitable bearings 15 and 16 within the casing and having a rotor 17 within a central cavity formed in the casing. The rotor carries a series of pumping elements in the form of radially movables vanes 18 mounted within radial slots opening to the periphery of the rotor with the vane position being controlled by a rotor ring 19 surrounding the rotor 17. The rotor and rotor ring are shown in FIG. 1 at maximum flow position with the rotor ring in an extreme position of non-concentricity relative to the rotor. This position is obtained under the urging of a governor indicated generally at 20 embodying a piston 21 engageable with the rotor ring and urged into engagement therewith by a governor spring 22 mounted in a housing 23 connected to the casing of the pump. At maximum pressure, the rotor ring 19 will be moved toward the left, as viewed in FIG. 1, to a position concentric with the rotor 17 against the force of spring 22. The rotor ring can have positions between that of concentricity with the rotor and the position shown. When the rotor ring is nearly concentric with the rotor, there is no flow, or substantially no flow, from the pump, and this is commonly referred to as the deadhead position or operation.

A pair of cylindrical plates 25 and 26 are positioned at opposite sides of the rotor and rotor ring to seal off the space between the outer periphery of the rotor and the inner periphery of the rotor ring 19. The plate 26 constitutes a port plate with a curved pressure port 27 communicating with the chambers between adjacent vanes 18 at the pressure side of the pump and a suction port 28 communicating with the chambers between adjacent vanes 18 at the suction side of the pump. The pressure port 27 communicates with a passage 30 in the casing leading to the outlet of the pump while the suction port 28 communicates with a passage 31 connecting to a source of fluid. In order to balance the pressure on the vanes, there are balancing ports 32 and 33, respectively, in fluid communication with the pressure port 27 and suction port 28.

To counteract a portion of the thrust derived from pressure within the pump, a movable thrust block 35 is movably mounted on a backup member 36 secured to a plate 37 attached to the casing of the pump and positioned for engagement with the rotor ring 19.

With the governor piston 21 and the axis of rotation of the pump rotor 17 defining a line on which the pump crossovers fall, it will be seen that the pressure port 27 lies to one side of this line and the suction port 28 to the other side. As the vanes cross this line in crossing over from pressure to suction, the space between adjacent vanes increases. This results in a decompression of fluid such as oil in the chamber between adjacent vanes, but pressure fluid can still discharge into the inlet port and become emulsified. Means are provided to drain oil oil from the chamber before it reaches the suction port 28. This means comprises a passage 40 formed in the port plate 26 having an inlet end 40a located in advance of the suction port 28 and communicating with the space between the rotor and the rotor ring and an outlet 40b connecting with the drain area of the pump outside the rotor ring 19. With this passage oil is drained off prior to the pumping chamber between adjacent vanes reaching the suction port so that the chamber can then receive a full charge of oil and the full charge will be carried around to the pressure port. This means that the oil arriving at the pressure port is at system pressure, and there is no possibility of oil flowing back into the pumping chambers from the pressure port which aids in obtaining smoother governor control of the pump. This passage also permits external drain flow at deadhead to make the unit quieter at deadhead and cause some flow of oil through the pump to obtain lower oil temperature and,

therefore, less slippage in the pump.

The passage means 40 is shown particularly in FIGS. 3 and 4, with its operative relation to the rotor 17 and the rotor ring 19. When in full flow operation, as shown in FIGS. 1 and 3, the passage inlet 40a is covered by the rotor ring 19 so as to not communicate with a chamber between adjacent vanes. Occasionally when the pump is operating at small pressure values at full flow operation, the passage 40 could become a suction line and if its connecting line to tank is not submerged, air could be drawn into the pump. So long as the connecting lines are submerged in the tank the passage 40 need not be obstructed at any time by the rotor ring 19 and can always be'in communication with a chamber between adjacent vanes. The operation at deadhead is shown particularly in FIG. 4 wherein the rotor ring 19 has moved to a position substantially concentric with the rotor 17 to fully expose the passage inlet 40a to the chamber between adjacent vanes immediately beyond crossover and in advance ofthe suction port 28. An added result derived from the passage 40 causing oil to flow to drain, is in reducing pressure beyond crossover acting against the rotor ring 19. This maintains the resultant of pressures acting against the rotor ring more nearly constant in both full flow and deadhead operation, with a resulting improvement in control by the governor spring 22. Additionally, it has been found that this substantially reduces the required spring rate of the governor spring.

We claim:

1. A variable volume hydraulic vane-type pump comprising, a casing, a rotor rotatable in said casing about an axis and having movable vanes, a rotor ring surrounding said rotor and movable between a position concentric with the rotor to place the pump in a no-flow state and a plurality of positions non-concentric with the rotor to deliver fluid from the pump, a yieldable governor engaging said rin and urging the ring away from the concentric position, plates at opposite sides ofthe rotor and ring with one of the plates having a pressure port and a suction port at opposite sides of a crossover point whereby as vanes approach said crossover and with the rotor ring nonconcentric the volume of the chamber between vanes becomes less and after moving past said crossover the volume of the chamber becomes greater, and a decompression passage in one of said plates having an inlet communicating with the chamber between a pair of vanes at a location between the suction port and at a distance from the crossover point at least equal to the space between a pair of vanes to connect said chamber to drain and discharge decompressed fluid to the drain.

2. A variable volume hydraulic vane-type pump comprising, a casing, a rotor rotatable in said casing about an axis and having movable vanes, a rotor ring surrounding said rotor and movable between a position concentric with the rotor to place the pump in a no-flow state and a plurality of positions non-concentric with the rotor to deliver fluid from the pump, a yieldable governor engaging said ring and urging the ring away from the concentric position, a port plate at one side of the rotor and ring and having a pressure port and a suction port, said governor and rotor axis defining a line with a pressure zone and the pressure port on one side of said line and the inlet zone and suction port at the other side of the line whereby as vanes approach said line and with the rotor ring non-concentric the volume of the space between vanes becomes less and after moving across said line the volume of the space becomes greater, and a decompression passage having an inlet communicating with the space between a pair of vanes at a location between said line and the suction port to always be blocked from the pressure port by a vane to drain oil pressure oil from the space between vanes before the space opens to the suction port to prevent aeration of fluid at the suction port.

3. A variable volume hydraulic vane-type pump as defined in claim 2 wherein said passage inlet is at a radial distance from said rotor axis to be covered by said rotor ring when the ring is in a plurality of positions near maximum non-concentricity with the rotor and to be uncovered when the rotor ring is more nearly concentric with the rotor.

4. A variable volume hydraulic vane-type pump comprising, a casing, a rotor rotatable in said casing about an axis and having movable vanes, a rotor ring surrounding said rotor and movable between a position concentric with the rotor to place the pump in a no-flow state and a plurality of positions non-concentric with the rotor to deliver fluid from the pump, a yieldable governor engaging said ring and uring the ring away from the concentric position, plates at the sides of the rotor and ring with one plate having a pressure port and a suction port, and means defining a passage in one of said plates having an inlet connected to the space between the rotor and ring at a position in advance of said suction port and at a distance from the crossover point where a space between vanes begins to expand rather than contract to always be blocked from the pressure zone in advance of the crossover point by a vane and an outlet to the casing drain area externally of the rotor ring, said passage inlet being at a radial distance from said axis to be covered by said rotor ring when in a plurality of positions near maximum non-concentricity and to be uncovered when the rotor ring moves to positions more nearly concentric.

References Cited UNITED STATES PATENTS 2,805,628 9/ 1957 Herndon et a1 10312O 3,070,020 12/ 1962 Pierce 1'03120 3,272,138 9/1966 Connoy et a1 103-120 DONLEY J. STOCKING, Primary Examiner.

WILBUR J. GOODLIN, Examiner. 

